John bubkhabdt



(No Model.)

J. BURKHARDT, METHOD OF FORMING HOLLOW SPHEROIDAL BODIES FROM SHEET METAL TUBES.

Patented Feb. 21, 1888.

Parser ries.

JOHN BURKHARDT, OF NEXV YORK, N. Y., ASSlGNOI-t OF ONE-IIALF TO WILLIAM H. JACKSON & COL, GF SAME PLACE.

METHOD OF FORMING HOLLOW SPHEROlDAL BODIES FROM SHEET-lllETAL TUBES.

@PECIFZ-EILATIGN forming part of Letters Patent No. 378,412, dated February 21, 1888.

Application filed January 3, 1887.

To all 2071-0712 it may concern.-

Be it known that I, J only Benin-manic, a citizen of the United States, residing at New York, in the county and State of New York, have discovered a new and useful process for converting seamless metal tubing into concavoconvcx oblate spheroidal bodies and imp ressiugthereon ornamental ligu res or designs; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being bad to the accompanying drawings, forming part of this specification.

In the production ofornamental metal-work, like railings, halusters, fenders, and similar articles,it has heretofore been the practice to make use of metal balls, either cast or spun of thin metal, to adorn such work.

The object of my invent-ion is to produce spheroidal concavo-convex ornaments from sect-ions of tubing. I make use of dies of the desired forms and sizes, in which a section of tubing of the proper length to form the hollow spheroidal body is placed to receive the action of a press. The dies may be made in two equal or unequal parts, and the upper one may be attached to the slide or plunger of a press, and the lower one may rest upon the platen or seat of the press. To produce these hollow spheroidal bodies of a shape and surface configuration resembling such objects as the pine-apple, the acorn, and other analogous forms, the shape and size of the two dies for forming these objects will be different. The interior concave surfaces of the dies may be made with embellishing figures thereon, or they may be made plain and embellishing figures of various designs may be impressed upon the spheroidal products by subsequent operation of the dies and press, the product being first covered with a thin elastic hardiuetal jacket made to represent in relief the particular design or figure to be imprinted upon it. It is obvious that these designs embodied in jackets may be produced in great variety. Before the second operation of the press (and after the product is formed) the latter may be filled with rosin or plaster to prevent tlisiiguration during the imprinting of designs thereon. The section of tubing to be used must be of large bore or orifice as Serial No. 223,203. (No model.

compared with the thickness of the metal which forms it, and will bcplacedin the lower die directly under the upper die that is attached to the slide of the press, and the compressing will begin simultaneously at both ends thereof and cause the metal to curve i11- wardly all around, and the dies will meet if the piece of tubing is of the proper length to form a globe, the dies of course being hemispherical for that purpose; but if the dies are of different forms or sizes, as would be necessary to form a body of the shape of the pineapple, the tube or blank will be proportionally longer, and the dies will meet at the line of the greatest diameter of the article produced.

In forming these spheroidal bodies a raised central girdle will be made around the article by stopping the action of the dies before they have reached the line of the greatest diameter 70 of the article. To form an aperture at the extremities of these ornamental hollow metal bodies, a stop at the base of the concavity of the dies may be used to limit the swagiug, upset-ting, and turning in of the metal at the ends of the section of tubing, whereby an aperture will be provided through or into which a rod, wire, or baluster may be inserted and secured, and such ba-lusl'er, rod, or piece of metal, made as the stem of a nut or apple, may be inserted through openings formed in the centers of the dies, and be secured to the spheroidal product by the operation of the press while the same is being formed, the dies serving to compress the metal around the rod or stem inserted through the openingsX and K.

In the accompanying drawings, Figures 1, 2, and 3 represent different shapes of these oblate-spheroidal concavoconvex bodies, such as may be formed of tubing by my process. 0 Fig. 4: represents a section of tubing of suitable length to form the product represented by Fig.

1 seated in the bottom concave die, a, ready to receive the compressive action of its countor-die. Fig. 5 exhibits the proper dimen- 5 sions of a section of tube to form the globe shown in Fig. 2. Fig. 6 represents a section of tube after having been subjected to the compression of one die only, the section being seated upon a plain platen with a solid core, 100

' ornamenting the exterior surface of the metal bodies formed in such dies.

A rod like cl, suitable for use as above stated, is shown in Fig. 3. above referred to, are intended for the insertion of the section of a baluster or rod to be used as part of a fender or railing, (Ste.

The openings K through dies shown in Fig. 7 are provided to permit the insertion of a rod, a baluster, or other piece of metal for the purpose mentioned, and similar openings corresponding therewith may be made through the platen of the press, and also through the slide or plunger ofthe press used to actuate the dies, for the introduction of such rod or baluster to the hollow metal body to be formed from a section of tubing, as specified. Such rod or other piece of metal will be inserted in proper position before the action of the press begins.

A iter a spheroidal hollow body is formed, as above described, by the use of plain dies, the article may be embellished by the use of a jacket embodying a design interposed between the article and the dies, and such design may be imprinted upon the article by the action of the press. Several simple designs embodied in flexible jackets may be successively imprinted upon the same article in the same manner and by the substitution of such jackets.

Having described my improved process of forming hollow spheroidal bodies, I would statet-hat I am aware that very small articles like beads have heretofore been shaped by compressing the ends only of tubular sections into a rounded form without shaping the pe riphery thereof, the tube being comparatively thick in relation to size ofthe article to be formed, so that sufficient body is provided in the tube to prevent crimping or doubling; and

The openings X,

I am aware that larger hollow articles have been swaged into more or less rounded form from comparatively thin tubular metal by first casting a thick temporary lining of soft metal into the tube to give body thereto, and then shaping in one or more sets of rounded dies; but my invention differs from the former in making bodies of any desired size without using tubing of a thickness increased as the diameter is enlarged, and also in not only swaging and upsetting the ends-of the tube into a smaller diameter, but also enlarging the diameter of the middle part thereof, and it differs from the latter most essentially in not employing lining ofsoft metal or any other material, and it differs from both in that, whereas in those cases there is only a changing of the shape of the tube, there is no upsetting of the metal, making it thinner in some parts and in others thicker. My process does thus greatly change the thickness of the metal in diff rent places, and, so far as I am aware, I am the first to discover that comparatively thin tubes of large diameter can be swaged and upset into spheroidal form by dies, and that the metal can thereby be upset without crimping to receive the desired forms. a

I claim as my invention- 1. The process herein described of forming hollow spheroidal bodies from thin sheet metal oblate at their extremities, which consists in first forming the metal into a tube, then placing a short section of said tube between two dies having the form of. the body to be made, and compressing the tube in the said dies.

2. The process described of embellishing spheroidal metal bodies, consisting of the interposition of flexible metal jackets in sections, embodying ornamental designs in relief, be tween such spheroidal bodies and the dies employed for forming the same, as set forth.

3. The process of attaching stems, rods, or sections of railings to concavo-convex spheroidal metal bodies, consisting of the compres sion of the metal of such bodies around the stems, rods, or railings during the operation of forming such spheroidal bodies, as set forth.

JOHN BURKHARDT.

\Vitnesses:

GEORGE MoHUeH, FRED. R. LAWRENCE. 

